Understanding Lnb Frequency and Transponder Frequencies

Topics: Low-noise block converter, Frequency, Antenna Pages: 5 (1562 words) Published: October 2, 2012
| Understanding LNB Frequencies and Transponder Frequencies « on: April 01, 2008, 07:44:50 PM »http://www.galaxy-marketing.com/satellite-support-forum1/index.php?topic=39.0| |

These are LNB types and frequencies:

DSS Circular LNB = 12.2GHz-12.7GHz
Standard FSS Linear LNB = 11.7GHz-12.2GHz
Universal FSS Linear LNB = 10.7GHz-12.7GHz

Keeping the above frequency range in mind, now let's look at the frequency ranges of your transponder.  Keep in mind that the transponder frequencies are presented in MHz. 

All DISH Network, DirecTV, and BEV satellites on DSS have transpnder frequencies that don't go below 12200MHz and don't go above 12700MHz.

All Ku band FSS satellites within North America have transponder frequencies ranging no less than 11700MHz and no more than 12200MHz.  For example, on Galaxy 25, the first Ku band transponder frequency is 11716 MHz and the last TP is 12177 MHz.

Now that you know this, cross reference the transponder frequencies and the LNB Input Frequency.  Does this start to make sense a bit more?

Universal LNBs
LNB (Low Noise Block)
A universal LNB can receive both polarizations and the full range of frequencies in both the Ku and C satellite band. Some LNBs can receive both polarizations simultaneously (through 2 different connectors), while other LNBs have either switchable or adjustable polarization. Typical Universal LNB specifications are:

* Local Oscillator (LO): 9.75 GHz /10.6 GHz
* Frequency: 10.7 GHz-12.75 GHz
* Noise Figure (NF): 0.7 dB
* Polarization: Linear
Standard DBS LNB example:
* Local Oscillator (LO): 11.25 GHz
* Frequency: 12.2 GHz-12.7 GHz
* Noise Figure (NF): 0.7 dB
* Polarization: Circular
Typical North American C-band LNB specs:
* Local Oscillator (LO): 5.15 GHz
* Frequency: 3.6-4.2 GHz
* Noise Figure (NF): 15 to 100 Kelvins (uses Kelvin ratings as opposed to dB rating) * Polarization: Linear
Dual and Quad LNBs are multiple LNBs in one package that allow for multiple receivers (on one dish). A Dual LNB consists of 2 universal LNBs (affixed at a small offset angle in a single housing) and uses only one “F” connector and coaxial cable connection to the converter box. Though also a Dual LNB system, the Monobloc LNB has only one output and only one (satellite) transmission as compared to dish systems that have two or more separate LNBs. Each LNB is connected to separate receivers in which both transmissions can be simultaneously viewed or recorded. The Monobloc LNB was specifically designed to receive signals from satellites that are spaced very close together. For example, parts of Europe use a Monobloc LNB to receive the Astra 1 (19E) and Hotbird (13E) satellites, eliminating the need for an expensive rotator. Quad Universal LNB (a.k.a. Quad-Output LNB)

The Quad Universal LNB can accommodate four separate receivers, as each receiver has independent control of band and polarization via 13v. and 17v. and 22kHz on/off switching respectively. This LNB is primarily deployed in the Sky Digiboxes (with 2 LNB inputs and internal hard disks for recording one program while the user watches another). Two LNB outputs would go to one “Sky Plus” Digibox, leaving the other 2 LNB outputs for either 2 standard Digiboxes or to one additional Sky Plus Digibox. OCTO LNBs

An OCTO LNB is the same as above, except that it has 8 independent outputs. Quattro Universal LNB’s
This is a 4-output LNB, specifically designed for use as a “head end” I.F. distribution system (for apartment complexes). LNBs can generally supply (up to) 16 outputs for separate dwellings or Digiboxes. The 4 outputs of the Quattro Universal LNB are: * Low band horizontal polarization

* High band horizontal polarization
* Low band vertical polarization
* High band vertical polarization
As a general rule of thumb, any standard (universal) LNB will work with any circular (prime focus) dish or offset focus dish....
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